Jump Consistent Hash

Python implementation of the jump consistent hash algorithm by John Lamping and Eric Veach[1]. Tested on Python 2.6, 2.7 and 3.4+.

Install

To install Jump Consistent Hash, simply run this simple command in your terminal of choice:

$ pip install jump-consistent-hash

Unless running PyPy the installation will try to compile the C++ reference implementation (unless an appropriate wheel is available). If it fails it will fallback to the pure Python implementation if it fails which is about 10x slower on CPython.

Usage

>>> import jump
>>> jump.hash(256, 1024)
520

If you want to use a str as a key instead of an int, you can pass it through a hash function to compute a real key. Here's a couple of examples using Python 3:

>>> import hashlib
>>> int(hashlib.md5(b'127.0.0.1').hexdigest(), 16)
325870950296970981340734819828239218902

>>> int(hashlib.sha1(b"127.0.0.1").hexdigest(), 16)
431133456357828263809343936597625557575256328153

>>> import binascii
>>> binascii.crc32(b'127.0.0.1') & 0xffffffff
3619153832

>>> abs(hash('127.0.0.1'))
7536019783825143230

Links

[1] http://arxiv.org/pdf/1406.2294v1.pdf